<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<style>
  .canvas{
    display: flex;
  }
  .box-list{
    background-color: #ccc;
    height: 100%;
    width: 240px;
    text-align: center;
    padding: 10px;
  }
  .box-list .box1{
    background-color: lightpink;
    width: 200px;
    height: 200px;
    margin: 0 auto ;
  }
  .box-list .box2{
    background-color: lightblue;
    width: 200px;
    height: 200px;
    margin: 0 auto ;
  }
  .container{
    width: calc(100vw - 250px);
    min-width: 800px;
    min-height: 100vh;
    border: 1px dashed #ccc;
    margin: 0 5px;
    margin-left: 100px;
  }
</style>
<body>
  <div class="canvas">
  <div class="box-list">
  <div class="box1" draggable="true"></div>
  <div class="box2" draggable="true"></div>
  </div>


  <div class="container"></div>
</div>
  <script src="index.js"></script>
</body>
</html>